1. Field of the Invention
The present invention relates to a calendar timer mechanism for turning on and off an object to be controlled at preset times and allowing preset times to be changed as desired, and a processing apparatus incorporating such a calendar timer mechanism.
2. Description of the Related Art
In the art of forming images, there have been used image forming apparatus for forming images captured for ultrasonic diagnosis, CT diagnosis, MRI diagnosis, or X-ray diagnosis, as visible images on recording mediums, e.g., photosensitive thermal-development recording mediums.
Such an image forming apparatus usually has a drum with a heater such as a halogen lamp or the like housed therein and an endless belt trained around about two-thirds of the outer circumferential surface of the drum for movement in unison with the drum. When the drum is rotated about its own axis, a photosensitive thermal-development recording medium is gripped between the drum and the endless belt and fed thereby. While the photosensitive thermal-development recording medium is fed, it is heated at a predetermined temperature for a predetermined period of time to thermally develop a latent image recorded on the photosensitive thermal-development recording medium.
The image forming apparatus described above is generally installed in a hospital, and is operated during preset periods of time on each day of the week. There has been a demand for a system for automatically controlling operation of the image forming apparatus according to a preset schedule which is established to turn on and off the power supply of the image forming apparatus on each day of the week.
One known automatic operation control system is disclosed in Japanese laid-open patent publication No. 6-337727, for example. According to the disclosed automatic operation control system, times to turn on and off the power supply connected to an apparatus which is to be automatically controlled for operation are set in advance, and next times to turn on and off the power supply are selected from the set times and set in a calendar timer device. When each of the times set in the calendar timer device is reached, the calendar timer device generates a signal and applies the signal to turn on or off the apparatus.
The disclosed automatic operation control system requires no external action to turn on and off the power supply, and allows the power supply to be turned on and off a plurality of times according to a single schedule setting.
The above image forming apparatus takes about 20 to 30 minutes, for example, to heat up the heater in the drum when the heater is turned from a turned-off state. Even though the heater is turned on at a time set by the calendar timer device, since the heater needs to be heated up after the time when it is turned on, a considerable period of time is required until an image forming process is actually started.
In particular, once the heater is turned off at a break such as a lunchtime or the like in the hospital, it will take some time after the heater is turned on next time until a next image forming process is started, resulting in a need for an unwanted standby time after the break. To avoid the inconvenient time consumption, it has been customary to keep the heater energized even during the break. This practice goes against efforts to save energy and hence is uneconomical.
The above problem is not limited to the image forming apparatus, but arises in connection with various other apparatus, and particularly poses serious disadvantages on various processing apparatus which have a structure requiring heating.